View Single Post
  #13   Report Post  
Posted to rec.audio.pro
Trevor Trevor is offline
external usenet poster
 
Posts: 2,820
Default Question re proper sealing of woofers with enclosure

On 9/09/2019 8:56 pm, geoff wrote:
On 9/09/2019 10:07 pm, Trevor wrote:
On 9/09/2019 8:33 am, geoff wrote:
On 9/09/2019 4:31 am, Rick Ruskin wrote:
The low end of my JBL 4315's sounds sounds less tight and defined
after having the 12" drivers refoamed.Â* I'm wondering if this could be
do to them not being sealed tightly enough with the enclosures.Â* Is
there any way to test for a proper seal without having to dismount
them and instal yet a another set of new seals?



---
This email has been checked for viruses by AVG.
https://www.avg.com


The 4315 is a ported cabinet, so a slight lack of seal (unlikely
anyway as the seal is, unless broken, a continuous ring) shouldn't
have a profound effect. More likely the new foams just a little stiff
and should loosen up with a bit of use to run them in.


Or more likely the new foams are a little stiffer than the old ones
and won't change at all. "running in" is more about you simply getting
used to the sound than any real and permanent measurable change in
actual performance.


In the past I have 'run in' a bass driver with noticeable change
(measured), and without hearing them at all during the process to
confuse matters.

Both a LF resonance and a level changed over 2 days at moderate power4
level - F downÂ* by a few Hz and and level up by a fraction of a dB. Same
position signal distance and everything else I could think of. Just
tilted back up from the sound-deadening wadding that it had been
inclined onto in order to cut down the noise in the basement.

This was elasticised paper surround.May not be the case for all drivers
or surround materials.


Yes there CAN be a change during "running in", but not as often as those
who rely on subjective listening alone like to imagine. Now my
experience in measuring speakers isn't extensive enough to make wild
claims, but I'll simply agree with Dick Pierce on the matter.